Breast Pump Sizing Kit
$
21.61
$
24.99
Free shipping & returns for Babylist orders $45+
FSA & HSA Eligible
1
Overview
Description
Find your perfect breast pump flange fit with a wide range of inserts designed for maximum pumping comfort and milk output.
The kit includes 13mm, 15mm, 17mm, 19mm, 21mm insert sets, a nipple sizing tool, pump sizing 101 guide and 1:1 virtual visit with a Willow Sizing Specialist.
Proper fit leads to comfort, and comfort leads to more milk output and fit starts with your flange.
What we about it
Helps you find the just-right breast pump flange fit.
Details
- Includes:
- 13mm, 15mm, 17mm, 19mm, 21mm insert sets
- Nipple Sizing Tool
- Pump Sizing 101 Guide
- 1:1 virtual visit with a Willow Sizing Specialist
- Connect with a Sizing Specialist for personalized guidance
- Use with any pump; they’re compatible with almost all 24mm flanges
- Fit most nipple sizes
Q&A
Have a question? Ask an expert.
Start typing and see existing answers.
Will these work on s1 spectra electric pump?
Best Answer: Yes, the Willow Breast Pump Sizing Kit should work with the Spectra S1 Electric Breast Pump, provided you're using 24 mm flanges.
Will these work with other breast pumps?
Best Answer: Yes. The Willow Breast Pump Sizing Kit is designed to work with more than just Willow pumps. The included silicone inserts are compatible with most 24 mm breast pump flanges, so you can use them with many other breast pump brands that have 24 mm flanges.
Keep in mind that the inserts are specifically made to fit 24 mm flanges. They are not universal for other flange sizes (such as 21 mm, 27 mm, or 28 mm), so compatibility depends on your pump's flange size.
Customer reviews
47 Ratings
1-10 of 47 Reviews
The sizing chart is super
This review was collected as part of a promotion
The sizing chart is super helpful and the flanges fit great. I just wish there was a way to order the size I need and not the entire sizing kit.
Sep 25, 2026
Easy to use- love that
This review was collected as part of a promotion
Easy to use- love that you get to try all of the sizes
Sep 8, 2026
So helpful to figure out
This review was collected as part of a promotion
So helpful to figure out the right size I needed!
Sep 5, 2026
Works great with my spectra
This review was collected as part of a promotion
Works great with my spectra and is super easy clean. The beast bump sizing kit starts with too small of a size. Only one size works for me.
Aug 25, 2026
Super helpful. Thank you!
This review was collected as part of a promotion
Super helpful. Thank you!
Aug 12, 2026
Easy to use, great value
This review was collected as part of a promotion
Easy to use, great value for the price!
Aug 9, 2026
Great addition to make pumping
This review was collected as part of a promotion
Great addition to make pumping unique to anyone. Didn’t think I needed custom sizing until I tried and was pleasantly surprised by the better fit.
Jun 22, 2026
I love that it comes
This review was collected as part of a promotion
I love that it comes with a lot of sizes!
Jun 16, 2026
This was so nice to
This review was collected as part of a promotion
This was so nice to have to help during the pumping journey.
Jun 12, 2026
I love that I can
This review was collected as part of a promotion
I love that I can get all sizes. Specially since each breast needs a different flange size. It is more cost effective to buy the sizing kit if you need two sets that are different sizes.
Jun 4, 2026
